In an electrophotographic image forming apparatus, generally, an electrostatic latent image is formed on a surface layer of a photoreceptor drum, and then the electrostatic latent image is developed by use of developer, such as toner, so that a developer image that is yet fixed is formed. Thereafter, a sheet recording medium is brought into contact with the photoreceptor drum by a transfer section to transfer the developer image to the recording medium. After the developer image is transferred, a fixing section applies heat and pressure to the developer image so that the developer image is fixed to the recording medium.
A photoreceptor drum with a so-called organic photoreceptor is widely used as the photoreceptor drum. The organic photoreceptor is manufactured by dispersing fine particles of photoconductive material into a mixture liquid in which a charge transport material and a resin are solved, and then applying the mixture liquid to a surface of a base of the drum and drying it, thereby forming a photoreceptor layer.
If foreign substances, such as residual fine-particle developer and a slip of paper, adhere to the surface layer of the photoreceptor drum and deteriorate, a film or a black spot of toner may be formed. Therefore, it is necessary to eliminate the foreign substances adhering to the surface. For this reason, a cleaning blade is provided in such a way as to be in contact with the photoreceptor drum, for the purpose of rubbing off the foreign substances adhering to the surface.
However, if the contact pressure of the blade is too low, then the foreign substances adhering to the surface of the photoreceptor drum are not eliminated sufficiently. As a result, the surface becomes significantly contaminated. This causes a negative effect such as formation of a film that is described above, and therefore the performance is degraded. Thus, the blade is brought into contact with the surface layer of the photoreceptor drum such that the surface layer is scoured to some degree, in order to recover the performance.
On the other hand, if the contact pressure of the blade is too high, then a problem may be caused that the surface of the photoreceptor drum may abraded unevenly due to scouring effect by an end part of the blade.
Accordingly, there has been a need for a technique that allows a surface layer of a photoreceptor drum to be cleaned suitably. Note that the term “scouring” in the description of the present application means scrapping more or less the photoreceptor layer.
Document 1 below teaches a conventional technique in which a surface layer of a photoreceptor drum is scoured so as to recover its performance.    [Document 1] Japanese Unexamined Patent Publication No. 204282/1993 (Tokukaihei 5-204282)(published on Aug. 13, 1993)
In the conventional technique, a driving force of a drive motor is transmitted to a feed roller and a photoreceptor drum via a first and second clutches. Specifically, the first clutch is turned on to transmit the driving force of the drive motor to the feed roller, and the feed roller feeds a recording sheet from a sheet feeding section to a transfer section, in normal feeding of recording sheets. The second clutch is also turned on so as to cause the photoreceptor drum to perform development and transferring at an appropriate timing.
On the other hand, during the scouring, an abrasive sheet including abrasive particles, instead of a recording sheet, is fed into a main body of the copying machine. The abrasive sheet is used to scour a photoreceptor drum of the copying machine. Then, while the abrasive sheet exists at the photoreceptor drum, the first clutch is turned off so as to stop the feeding of the abrasive sheet. While the abrasive sheet is kept in contact with the photoreceptor drum, the second clutch is turned on so that the driving force of the drive motor is transmitted to the photoreceptor drum. This causes the photoreceptor drum to be rotated so as to allow the abrasive sheet to scour the surface layer of the photoreceptor drum.
Further, a similar technique is taught in Document 2 below.    [Document 2] Japanese Unexamined Patent Publication No. 185302/1997 (Tokukaihei 9-185302)(published on Jul. 15, 1997)
However, with the techniques of Documents 1 and 2, it is necessary to place a special abrasive sheet, in addition to a recording sheet, at the feeding section, for the purpose of eliminating the foreign substances adhering to the surface of the photoreceptor. This causes an inconvenience in handling. Furthermore, the special abrasive sheet is used so that it becomes necessary to provide a feeding section, in addition to the sheet feeding section, for storing the special abrasive sheets. This causes the structure of the apparatus, especially the structure relating to the sheet feeding section such as a feeding section of the copying machine, to be complicated. Therefore, miniaturization of the apparatus, improvement in economical efficiency, and facilitation of maintenance are disturbed.